ALife 2026 · Toronto

CARL Soliton Creation Demo

From The Artificial Experimentalist: Discovery and Control of Self-Organizing Phenomena with Autotelic Reinforcement Learning — Cvjetko, Hartl, Levin, Moulin-Frier & Oudeyer.

CARL is a goal-conditioned reinforcement learning agent that is able to guide the dynamics of Lenia (continuous cellular automaton) towards desired states through a sequence of local interventions. In this demo, CARL was trained to drive the grid's total mass towards some target value. At each step, CARL can select a spot on the board and either inject or erase mass there. The reward makes no reference to shape or structure, but because actions are costly, a self-sustaining configuration that matches the target is cheaper than intervening indefinitely. Soliton creation therefore emerges as a byproduct of reward maximization: the agent builds a localized, persistent pattern, a soliton, and stops acting once it holds the target mass on its own. Drag the target τ and watch CARL chase it, or pick a soliton recipe (hand-selected hyperparameters) to see what it can grow.

Hover the ? badges next to the controls for more detail.

Performance. The Lenia simulation and the policy network both run on your device, on the CPU only, and are computationally demanding. If playback stutters, reduce the board size, lower the simulation speed, and set your machine to a high-performance power mode. Tested in desktop Chrome and Brave.

CARL is acting
total mass 0/100
τ
steps 0 actions 0 infer rate clock 0.00
adding mass removing mass target mass τ

CARL acts for 150 steps, then pauses so you can watch the pattern evolve. Loop keeps it acting.

Soliton recipe ?

Update rule ?

Xt+dt = [ Xt + dtφ (KXt) ] 0 1

kernel K
growth φ(u)

Goal ?

Action & world ?